<p>The change of current determined with the EG-ISFET sensor is represented as a function o... more <p>The change of current determined with the EG-ISFET sensor is represented as a function of trehalose concentration. The sensing cells depicted as closed red squares, whereas the control cells are shown as closed blue circles.</p
<p>The reference voltage (V) is shown as a function of pH evaluated at a reference current ... more <p>The reference voltage (V) is shown as a function of pH evaluated at a reference current of 100 μA.</p
<p>The change of current generated from the AD and control groups. Data are presented as me... more <p>The change of current generated from the AD and control groups. Data are presented as median. *<i>p</i> ≤ 0.05.</p
In this study, a high-performance bio-organic memristor with a crossbar array structure using mil... more In this study, a high-performance bio-organic memristor with a crossbar array structure using milk as a resistive switching layer (RSL) is proposed. To ensure compatibility with the complementary metal oxide semiconductor process of milk RSL, a high-k Ta2O5 layer was deposited as a capping layer; this layer enables high-density, integration-capable, photolithography processes. The fabricated crossbar array memristors contain milk–Ta2O5 hybrid membranes, and they exhibit bipolar resistance switching behavior and uniform resistance distribution across hundreds of repeated test cycles. In terms of the artificial synaptic behavior and synaptic weight changes, milk–Ta2O5 hybrid crossbar array memristors have a stable analog RESET process, and the memristors are highly responsive to presynaptic stimulation via paired-pulse facilitation excitatory post-synaptic current. Moreover, spike-timing-dependent plasticity and potentiation and depression behaviors, which closely emulate long-term pl...
In this study, the efficient fabrication of nickel silicide (NiSix) Schottky barrier thin-film tr... more In this study, the efficient fabrication of nickel silicide (NiSix) Schottky barrier thin-film transistors (SB-TFTs) via microwave annealing (MWA) technology is proposed, and complementary metal-oxide-semiconductor (CMOS) inverters are implemented in a simplified process using ambipolar transistor properties. To validate the efficacy of the NiSix formation process by MWA, NiSix is also prepared via the conventional rapid thermal annealing (RTA) process. The Rs of the MWA NiSix decreases with increasing microwave power, and becomes saturated at 600 W, thus showing lower resistance than the 500 °C RTA NiSix. Further, SB-diodes formed on n-type and p-type bulk silicon are found to have optimal rectification characteristics at 600 W microwave power, and exhibit superior characteristics to the RTA SB-diodes. Evaluation of the electrical properties of NiSix SB-TFTs on excimer-laser-annealed (ELA) poly-Si substrates indicates that the MWA NiSix junction exhibits better ambipolar operation ...
This study proposes a bidirectional chemical sensor platform using ambipolar double-gate ion-sens... more This study proposes a bidirectional chemical sensor platform using ambipolar double-gate ion-sensitive field-effect transistors (ISFET) with microwave-assisted Ni-silicide Schottky-barrier (SB) source and drain (S/D) on a fully depleted silicon-on-insulator (FDSOI) substrate. The microwave-assisted Ni-silicide SB S/D offer bidirectional turn-on characteristics for both p- and n-type channel operations. The p- and n-type operations are characterized by high noise resistance as well as improved mobility and excellent drift performance, respectively. These features enable sensing regardless of the gate voltage polarity, thus contributing to the use of detection channels based on various target substances, such as cells, antigen-antibodies, DNA, and RNA. Additionally, the capacitive coupling effect existing between the top and bottom gates help achieve self-amplified pH sensitivity exceeding the Nernst limit of 59.14 mV/pH without any additional amplification circuitry. The ambipolar FE...
2019 Joint International EUROSOI Workshop and International Conference on Ultimate Integration on Silicon (EUROSOI-ULIS), 2019
We proposed a silicon-on-insulator (SOI) based coplanar dual gate ion-sensitive field-effect tran... more We proposed a silicon-on-insulator (SOI) based coplanar dual gate ion-sensitive field-effect transistor (Cop-DG-ISFET) pH sensor to improve the performance of conventional ISFET pH sensors. Cop-DG-ISFET employs coplanar dual gates consisting of a control gate (CG) and a sensing gate (SG) over the channel, and a floating gate (FG) under the channel. Since CG and SG are capacitively coupled to FG, both gates can be used to modulate FET channel conductance. As a result, this device can amplify the sensing signal according to the capacitive coupling ratio between FG and coplanar gates (CG or SG). Since the amplification factor can be adjusted by the capacitance ratio of SG and CG, the pH sensitivity is improved by reducing the CG area compared to the SG area. Moreover, we evaluated the stability of the device by measuring the hysteresis width and drift rate, and found the stability was improved when the sensitivity was taken into consideration. Therefore, the SOI-based Cop-DG-ISFET sensor is expected to be a promising point-of-care biosensor application platform with a simple structure and excellent sensitivity and stability.
In this study, we propose the fabrication of sol-gel composite-based flexible and transparent syn... more In this study, we propose the fabrication of sol-gel composite-based flexible and transparent synaptic transistors on polyimide (PI) substrates. Because a low thermal budget process is essential for the implementation of high-performance synaptic transistors on flexible PI substrates, microwave annealing (MWA) as a heat treatment process suitable for thermally vulnerable substrates was employed and compared to conventional thermal annealing (CTA). In addition, a solution-processed wide-bandgap amorphous In-Ga-Zn (2:1:1) oxide (a-IGZO) channel, an organic polymer chitosan electrolyte-based electric double layer (EDL), and a high-k Ta2O5 thin-film dielectric layer were applied to achieve high flexibility and transparency. The essential synaptic plasticity of the flexible and transparent synaptic transistors fabricated with the MWA process was demonstrated by single spike, paired-pulse facilitation, multi-spike facilitation excitatory post-synaptic current (EPSC), and three-cycle evalu...
In this work, the analog performances of n-MOSFET fabricated on strained-Si/relaxed Si buffer lay... more In this work, the analog performances of n-MOSFET fabricated on strained-Si/relaxed Si buffer layer with Ge mole fractions and thermal annealing temperatures after device fabrication have been characterized in Depth. The effective electron mobility was increased with the increase of Ge mole fraction for all annealing temperatures. However the effective electron mobility was decreased at the Ge mole fraction of 32%. The analog performances were enhanced with the increase of Ge mole fraction at the room temperature but they were degraded at the Ge mole fraction of 32%. Since the degradation of the effective electron mobility of strained-Si layer is more significant than one of conventional Si layer at elevated temperature, the degradation of analog performances of SGOI devices were increased than those of SOI devices.
In this study, we applied microwave annealing (MWA) to fabricate amorphous In-Ga-Zn-O (a-IGZO) th... more In this study, we applied microwave annealing (MWA) to fabricate amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) without thermal damage to flexible polyimide (PI) substrates. Microwave energy is highly efficient for selective heating of materials when compared to conventional thermal annealing (CTA). We applied MWA and CTA to a-IGZO TFTs on PI substrate to evaluate the thermal damage to the substrates. While the PI substrate did not suffer thermal damage even at a high power in MWA, it suffered severe damage at high temperatures in CTA. Moreover, a-IGZO TFTs were prepared by MWA at 600 W for 2 min, whereas the same process using CTA required 30 min at a temperature of 300 °C, which is a maximum process condition in CTA without thermal damage to the PI substrate. Hence, MWA TFTs have superior electrical performance when compared to CTA TFTs, because traps/defects are effectively eliminated. Through instability evaluation, it was found that MWA TFTs were more stable than CT...
<p>The change of current determined with the EG-ISFET sensor is represented as a function o... more <p>The change of current determined with the EG-ISFET sensor is represented as a function of trehalose concentration. The sensing cells depicted as closed red squares, whereas the control cells are shown as closed blue circles.</p
<p>The reference voltage (V) is shown as a function of pH evaluated at a reference current ... more <p>The reference voltage (V) is shown as a function of pH evaluated at a reference current of 100 μA.</p
<p>The change of current generated from the AD and control groups. Data are presented as me... more <p>The change of current generated from the AD and control groups. Data are presented as median. *<i>p</i> ≤ 0.05.</p
In this study, a high-performance bio-organic memristor with a crossbar array structure using mil... more In this study, a high-performance bio-organic memristor with a crossbar array structure using milk as a resistive switching layer (RSL) is proposed. To ensure compatibility with the complementary metal oxide semiconductor process of milk RSL, a high-k Ta2O5 layer was deposited as a capping layer; this layer enables high-density, integration-capable, photolithography processes. The fabricated crossbar array memristors contain milk–Ta2O5 hybrid membranes, and they exhibit bipolar resistance switching behavior and uniform resistance distribution across hundreds of repeated test cycles. In terms of the artificial synaptic behavior and synaptic weight changes, milk–Ta2O5 hybrid crossbar array memristors have a stable analog RESET process, and the memristors are highly responsive to presynaptic stimulation via paired-pulse facilitation excitatory post-synaptic current. Moreover, spike-timing-dependent plasticity and potentiation and depression behaviors, which closely emulate long-term pl...
In this study, the efficient fabrication of nickel silicide (NiSix) Schottky barrier thin-film tr... more In this study, the efficient fabrication of nickel silicide (NiSix) Schottky barrier thin-film transistors (SB-TFTs) via microwave annealing (MWA) technology is proposed, and complementary metal-oxide-semiconductor (CMOS) inverters are implemented in a simplified process using ambipolar transistor properties. To validate the efficacy of the NiSix formation process by MWA, NiSix is also prepared via the conventional rapid thermal annealing (RTA) process. The Rs of the MWA NiSix decreases with increasing microwave power, and becomes saturated at 600 W, thus showing lower resistance than the 500 °C RTA NiSix. Further, SB-diodes formed on n-type and p-type bulk silicon are found to have optimal rectification characteristics at 600 W microwave power, and exhibit superior characteristics to the RTA SB-diodes. Evaluation of the electrical properties of NiSix SB-TFTs on excimer-laser-annealed (ELA) poly-Si substrates indicates that the MWA NiSix junction exhibits better ambipolar operation ...
This study proposes a bidirectional chemical sensor platform using ambipolar double-gate ion-sens... more This study proposes a bidirectional chemical sensor platform using ambipolar double-gate ion-sensitive field-effect transistors (ISFET) with microwave-assisted Ni-silicide Schottky-barrier (SB) source and drain (S/D) on a fully depleted silicon-on-insulator (FDSOI) substrate. The microwave-assisted Ni-silicide SB S/D offer bidirectional turn-on characteristics for both p- and n-type channel operations. The p- and n-type operations are characterized by high noise resistance as well as improved mobility and excellent drift performance, respectively. These features enable sensing regardless of the gate voltage polarity, thus contributing to the use of detection channels based on various target substances, such as cells, antigen-antibodies, DNA, and RNA. Additionally, the capacitive coupling effect existing between the top and bottom gates help achieve self-amplified pH sensitivity exceeding the Nernst limit of 59.14 mV/pH without any additional amplification circuitry. The ambipolar FE...
2019 Joint International EUROSOI Workshop and International Conference on Ultimate Integration on Silicon (EUROSOI-ULIS), 2019
We proposed a silicon-on-insulator (SOI) based coplanar dual gate ion-sensitive field-effect tran... more We proposed a silicon-on-insulator (SOI) based coplanar dual gate ion-sensitive field-effect transistor (Cop-DG-ISFET) pH sensor to improve the performance of conventional ISFET pH sensors. Cop-DG-ISFET employs coplanar dual gates consisting of a control gate (CG) and a sensing gate (SG) over the channel, and a floating gate (FG) under the channel. Since CG and SG are capacitively coupled to FG, both gates can be used to modulate FET channel conductance. As a result, this device can amplify the sensing signal according to the capacitive coupling ratio between FG and coplanar gates (CG or SG). Since the amplification factor can be adjusted by the capacitance ratio of SG and CG, the pH sensitivity is improved by reducing the CG area compared to the SG area. Moreover, we evaluated the stability of the device by measuring the hysteresis width and drift rate, and found the stability was improved when the sensitivity was taken into consideration. Therefore, the SOI-based Cop-DG-ISFET sensor is expected to be a promising point-of-care biosensor application platform with a simple structure and excellent sensitivity and stability.
In this study, we propose the fabrication of sol-gel composite-based flexible and transparent syn... more In this study, we propose the fabrication of sol-gel composite-based flexible and transparent synaptic transistors on polyimide (PI) substrates. Because a low thermal budget process is essential for the implementation of high-performance synaptic transistors on flexible PI substrates, microwave annealing (MWA) as a heat treatment process suitable for thermally vulnerable substrates was employed and compared to conventional thermal annealing (CTA). In addition, a solution-processed wide-bandgap amorphous In-Ga-Zn (2:1:1) oxide (a-IGZO) channel, an organic polymer chitosan electrolyte-based electric double layer (EDL), and a high-k Ta2O5 thin-film dielectric layer were applied to achieve high flexibility and transparency. The essential synaptic plasticity of the flexible and transparent synaptic transistors fabricated with the MWA process was demonstrated by single spike, paired-pulse facilitation, multi-spike facilitation excitatory post-synaptic current (EPSC), and three-cycle evalu...
In this work, the analog performances of n-MOSFET fabricated on strained-Si/relaxed Si buffer lay... more In this work, the analog performances of n-MOSFET fabricated on strained-Si/relaxed Si buffer layer with Ge mole fractions and thermal annealing temperatures after device fabrication have been characterized in Depth. The effective electron mobility was increased with the increase of Ge mole fraction for all annealing temperatures. However the effective electron mobility was decreased at the Ge mole fraction of 32%. The analog performances were enhanced with the increase of Ge mole fraction at the room temperature but they were degraded at the Ge mole fraction of 32%. Since the degradation of the effective electron mobility of strained-Si layer is more significant than one of conventional Si layer at elevated temperature, the degradation of analog performances of SGOI devices were increased than those of SOI devices.
In this study, we applied microwave annealing (MWA) to fabricate amorphous In-Ga-Zn-O (a-IGZO) th... more In this study, we applied microwave annealing (MWA) to fabricate amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) without thermal damage to flexible polyimide (PI) substrates. Microwave energy is highly efficient for selective heating of materials when compared to conventional thermal annealing (CTA). We applied MWA and CTA to a-IGZO TFTs on PI substrate to evaluate the thermal damage to the substrates. While the PI substrate did not suffer thermal damage even at a high power in MWA, it suffered severe damage at high temperatures in CTA. Moreover, a-IGZO TFTs were prepared by MWA at 600 W for 2 min, whereas the same process using CTA required 30 min at a temperature of 300 °C, which is a maximum process condition in CTA without thermal damage to the PI substrate. Hence, MWA TFTs have superior electrical performance when compared to CTA TFTs, because traps/defects are effectively eliminated. Through instability evaluation, it was found that MWA TFTs were more stable than CT...
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